<!DOCTYPE html>
<html>
<head>
  <meta name='viewport' content='width=device-width'/>
  <style>
    body {
      margin: 0px;
    }
    #content {
      width: 0px;
      height: 0px;
    }
  </style>
</head>

<body>
  <div id="content">a</div>
</body>

</html>
